Comparison of Ground-Based Ionospheric Scintillation Observations With In Situ Electron Density Variations as Measured by the Swarm Satellites

Abstract

Ionospheric scintillation is known to be associated with irregularities in electron density, which manifests as rapid fluctuations in the amplitude and phase of radio signals traversing the ionosphere. The scintillations caused by irregularity structures in the ionosphere can be directly measured using ground-based GPS scintillation measurement receivers. In this work we have used in situ measurements of electron density by means of the Langmuir probe on the Swarm satellites to derive an index called the rate of density index (RODI). Using a ground-based International Global Navigation Satellite Systems Service receivers and one dedicated scintillation measurement receiver, we have examined if we can identify ionospheric scintillation events that are correlated with space-based electron density variations characterized by the RODI for cases when the Swarm satellites orbital tracks traverse coincidental locations to the ground-based station. The selected Swarm B passes over Africa have been limited to the longitudes within ±7° of longitude relative to the position of a dedicated scintillation receiver located at Pwani, Kenya (Geo. Lon: 39.78°E, Geo. Lat: 3.24°S). Our results show that RODI could be a useful index for detecting irregularities associated with scintillation events that can also be observed from the ground. There is a similarity in RODI fluctuations and ground-based irregularity measures based on rate of total electron content index with an asymmetry in irregularity activity across African region. There is stronger irregularity activity and high background nighttimes electron density on the western side of Africa than on the eastern side. This work shows the potential of using space-based in situ measurement for scintillation detection and mitigation for operational purposes particularly for regions where terrestrial scintillation measurement are not possible like over oceans and deserts.